Switching assemblies having a switching device associated with a power distribution plate and a heat sink are known in the art. Generally, these switching devices are semiconductors that utilize high current transistors. Operation of a high current switching device produces a large amount of heat proportional to the respective size of the device. Furthermore, the power distribution plate or bus bar used with the high current device also carries a relatively high level of current that generates even more heat. The combined heat generated by the bus bar and switching device is sufficient to damage electrical components within the switching device. Therefore, the heat generated within the switching device and the bus bar must be drawn away by a heat sink to prevent damage to the electrical components.
High current switching devices are used in combination with high performance motors and generators, as found in automobiles and other motorized vehicles. Advancement in motor and generator technology, and more specifically the inclusion of electrical controls and computers with such devices, has compounded the need for better performing switching devices. More specifically, technological advancements now require switching assemblies to incorporate (1) a compact package, (2) a low resistance power distribution plate or bus bar, (3) low inductance of the overall switching assembly, and (4) superior heat dissipation.
One example of an advancement in generator and motor technology that requires improved switching assemblies is the Integrated Starter Alternator Damper (ISAD) device. The ISAD is a sophisticated system that replaces starters, flywheels, generators, and dampers in vehicles. The ISAD requires sophisticated switching assemblies having superior functional characteristics to provide high current and voltage for their various electromechanical components, which include electronic controls and sensors.
With these considerations in mind, the known art provides bus bars that are mechanically attached to the top of switching devices. These bus bars are usually heavy, solid metal structures that carry considerable current and generate substantial heat. The switching devices typically use high current transistors, such as Integrated Gate-type Bipolar Transistors (IGBT) or Field-effect Transistors (FET). A heat sink is attached to the switching device in order to dissipate heat produced by the bus bar and the switching device. As known in the art, heat sinks may comprise parallel copper or aluminum plates carrying a coolant gas or liquid therebetween.
Considering the power and current demands of modern applications, the known art separates the bus bar and heat sink in a manner that is either unworkable or damaging to the switching device. Thus, there is a need for a switching or bus bar assembly having a switching device, bus bar, and heat sink, wherein the bus bar and heat sink are adjacent to one another and more compact is size.